The Who, What, When, Where and Why of Chemistry
Chemistry is not a world unto itself. It is woven firmly into the fabric of the rest of the world, and various fields, from literature to archeology, thread their way through the chemist's text.

I was browsing the paper version C&E News on the train yesterday afternoon, and noticed two back to back advertisements for halogens, one for bromine reclamation, the other for iodine. Prilled iodine to be precise. Prilled? I had a vision of lacy violets frills.

Prills are tiny balls of a substance, formed by letting droplets of the liquid fall from a height (in a prilling tower.) Surface tension has its way and the droplets become spheres, which then solidify. Many bulk industrial chemicals, particularly fertilizers and detergents, are prilled for easier handling.

Prilling has its roots in 18th century copper mining, referring to beads of high purity copper.

While I rarely buy chemicals, I have purchased iodine flakes for a teaching lab. The catalog does offer me the choice of "iodine, beads" — prills by another name.